This invention relates to a bipolar electrosurgical instrument for use in the bulk removal of tissue, as in a laparoscopic hysterectomy.
In a laparoscopic hysterectomy, the body of the uterus is resected from the stump or fundus, and then removed from the operative site. To enable the uterus to be removed through a limited surgical opening, it is desirable to morcellate it into relatively smaller pieces of tissue, which are easier to remove. Our pending patent application, published as WO05/112806 describes an electrosurgical morcellator for the bulk removal of tissue. The present invention relates to an improvement to this type of instrument.
A known problem with morcellating devices is their tendency to “coring”, in which the tip of the morcellator dives into the tissue in a relatively uncontrolled way. A preferred cutting technique is to use the device in a “peeling” action, in which the cutting instrument removes tissue from the outside of an organ, rather like the peeling of an apple or orange. Peeling is preferred to coring for several reasons. A first reason is that the tip of the morcellator is more visible to the surgeon if it is peeling around the outside of the tissue, as opposed to being buried within the tissue as happens when the instrument is producing a core of tissue. Peeling produces a more continuous cut, and also a more continuous mass of uncut tissue. The more continuous cut means that the process can be completed more quickly, with the surgeon having to re-engage the tissue less often. Peeling from the outside of a solid organ or mass of tissue leaves behind a more continuous mass of tissue, and less tissue fragments as compared with coring.
Published US patent application 2008/0039883 describes the problem with coring, and provides a mechanical solution in the form of a protrusion situated at the distal tip of the instrument. The present invention attempts to provide an alternative solution, more suited to use with an electrosurgical morcellator.